Sensitivity Analysis
The results of heterogeneity and pleiotropy analyses can be found in Table 1. Cochran’s Q test conducted for both MR Egger and IVW indicated no evidence of heterogeneity among these SNPs (P > 0.05). Similarly, in the funnel plots of IVW and MR Egger, no significant heterogeneity between IVs was observed (Figure S1).
Furthermore, as shown in Table 1, in the pleiotropy analysis, the MR Egger regression test did not reveal any evidence of directional pleiotropy. The results of MR-PRESSO global test also indicated that there was no directional pleiotropy and that there were no outliers for any IVs. This suggests that the obtained results are unlikely to be influenced by any potential biases.
Additionally, the leave-one-out test showed that the causal estimation of genetically predicted telomere length on the quantity of lymphocytes was not influenced by single SNP (Figure S2). No matter which SNP was removed, it would exert no fundamental effect on the results, implying the stability of our two-sample MR analysis.